Author Archives: Steven Dufresne

Ken Shirriff Found Butterflies In His Op-Amp

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In 1976, Texas Instruments came out with the TL084, a four JFET op-amp IC each with similar circuitry to Fairchild’s very popular single op-amp 741. But even though the 741 has been covered in detailed, when [Ken Shirriff] focused his microscope on a TL084, he found some very interesting things.

To avoid using acid to get at the die, he instead found a ceramic packaged TL084 and pried off the cover. The first things he saw were four stabilizing capacitors, by far the largest structures on the die and visible to the naked eye.

When he peered into his microscope …read more

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Building A Mini Electric Bike In Between Projects

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What do you do when you suddenly find you have some free time because you’re waiting on parts or have run up against other delays for your current project? If you’re [James Bruton], you design and build a mini electric bike.

Being a prolific builder, [James] already had the parts he needed. Some of them were left over from previous projects: a small motor, a 24 volt LiPo battery, an SK8 electronic speed controller, and a twist grip for the handlebars. He cut a wooden frame using his CNC machine and 3D printed various other components. Normally he uses ABS …read more

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Makerbot Printer Reborn As PCB Engraver

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Makerbot 3D printers were among the first to hit the market, so it makes sense that old and broken ones now litter the shelves of hackerspaces and home workshops alike. Rather than throw his one out, [Foaly] saw an opportunity to convert it to some sort of CNC machine. Given its lack of inherent rigidity and relatively weak motors, he opted to make a low-impact circuit board engraver which he appropriately calls the MakerbotCNC. We like the thought he put into this project, and it was clearly backed by plenty of experience.

Fortunately, his Makerbot Replicator 2 stemmed from a …read more

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[Festo’s] Underwater Robot Uses Body-Length Fins

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[Festo] have come up with yet another amazing robot, a swimming one this time with an elegant propulsion mechanism. They call it the BionicFinWave. Two fins on either side almost a body-length long create a wave which pushes water backward, making the robot move forward. It’s modeled after such fish as the cuttlefish and the Nile perch.

What was their elegant solution for making the find undulate? Nine lever arms are attached to each fin. Those lever arms are controlled by two crankshafts which extend from the front of the body to the rear, one for each side. A servo …read more

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Make A Natural Language Phone Bot Like Google’s Duplex AI

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After seeing how Google’s Duplex AI was able to book a table at a restaurant by fooling a human maître d’ into thinking it was human, I wondered if it might be possible for us mere hackers to pull off the same feat. What could you or I do without Google’s legions of ace AI programmers and racks of neural network training hardware? Let’s look at the ways we can make a natural language bot of our own. As you’ll see, it’s entirely doable.

Breaking Down The Solution

One of the first steps in engineering a solution is to break …read more

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Federico Faggin: The Real Silicon Man

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While doing research for our articles about inventing the integrated circuit, the calculator, and the microprocessor, one name kept popping which was new to me, Federico Faggin. Yet this was a name I should have known just as well as his famous contemporaries Kilby, Noyce, and Moore.

Faggin seems to have been at the heart of many of the early advances in microprocessors. He played a big part in the development of MOS processors during the transition from TTL to CMOS. He was co-creator of the first commercially available processor, the 4004, as well as the 8080. And he was …read more

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Making Robot Snakes That Slither, Sidewind, And Strike

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[Will Donaldson] has been making robot snakes of all sorts. One of his snakes hugs the ground, slithering across it with a sine wave motion. Flipping it on its side and calling different code, that same snake also moves like an inchworm. Another of his snakes lifts parts of itself upward to move sideways across the ground, again using sine waves.

At first, his slithering snake would only oscillate in place on the floor. Looking more closely at biological snakes, he found that part of the reason they moved forward was due to their scales. The scales move smoothly over …read more

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Espresso Machine From Motorbike Engine Parts

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[Rulof Maker] is a master at making things from salvaged parts, and being an Italian lover of espresso coffee, this time he’s made an espresso machine. The parts in question are a piston and cylinder from an old motorbike, believe it or not, and parts from an IKEA lamp.

Why the piston and cylinder? For those not familiar with espresso machines, they work by forcing pressurized, almost boiling water through ground coffee. He therefore puts the water in the piston cylinder, and levers the piston down onto it, forcing the water out the bottom of the cylinder and through the …read more

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[James Bruton] Is Making A Dog: OpenDog Project

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There was a time when a two-legged walking robot was the thing to make. But after seeing years of Boston Dynamic’s amazing four-legged one’s, more DIYers are switching to quadrupeds. Now we can add master DIY robot builder [James Bruton] to the list with his openDog project. What’s exciting here is that with [James’] extensive robot-building background, this is more like starting the challenge from the middle rather than the beginning and we should see exciting results sooner rather than later.

Thus far [James] has gone through the planning stage, having iterated through a few versions using Fusion 360, and …read more

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No Microcontroller In This Vending Machine, D’oh!

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You might think that a microcontroller would be needed to handle a vending machine’s logic. For one thing, only the correct change should activate them and the wrong change should be returned.  If the correct change was detected then a button press should deliver the right food to the dispenser. But if you like puzzles then you might try to think of a way to do with without a microcontroller. After all, the whole circuit can be thought of as a few motors, a power source, and a collection of switches, including the right sized coin.

That’s the way [Little …read more

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